Delaney passed the Florida Bar exam in 1981[1] and was hired by then State AttorneyEd Austin, eventually becoming Austin's Chief Assistant State Attorney. When Austin was elected Mayor of Jacksonville in 1991, Delaney became the city's General Counsel for a short time, and then served as Austin's chief of staff. Delaney ran for mayor himself in 1995 when Austin declined to seek a second term.

In 1995, Delaney defeated former mayor Jake Godbold to become mayor of Jacksonville, Florida, serving two consecutive terms from 1995 to 2003. He was the first Republican elected to the position since 1888. He was succeeded by John Peyton in July 2003.

During his mayoral term, Delaney was noted for launching the Better Jacksonville Plan, a massive, billion dollar package of projects for municipal improvements funded by a sales tax increase, as well as the Preservation Project, a series of land grants for parks. He was one of the most popular mayors in Jacksonville's history, enjoying consistently high approval ratings and running unopposed for his second election. In 2003, he received the President's Conservation Achievement Award from The Nature Conservancy for the Preservation Project.[2]

Delaney was appointed President of the University of North Florida (UNF) in 2003. During his tenure the university has seen a surge of building projects, including a new Student Union and other facilities.[3][4] Under his leadership, the university launched an initiative to identify and strengthen its top "flagship" programs.[3] Since 2005, six programs have been established as flagships: Nursing, Transportation and Logistics, International Business, Coastal Biology, Nutrition and Dietetics, and Music.[5]